The invention relates to an omnibus suitable for train formation of the type disclosed for example in German Published Unexamined Patent Application (DE-OS) 2,643,325.
In the case of the known omnibus, the front coupling and the rear coupling are not attached fixedly but are laterally displaceable in arc-shaped horizontally running guide rails. To be precise the guide rails are curved in each case concentrically to the center point of the driven rear axle of the omnibus. In this way, when omnibuses are coupled together, the laterally displaceable coupling device brings itself into the connecting line between the center point of the driven rear axle of the front bus and the center point of the driven rear axle of the rear bus. The point of this arrangement is to exert on omnibuses coupled together transverse forces, directed towards the outside of the bend, by reaction forces within the coupling device. The intention is that the transverse forces tend to urge the track-guided buses toward the lateral guide flange on the side of the outside of the bend and to ensure track guidance along the lateral guide flange on the outside of the bend, because a contact of the track guidance elements with the corresponding lateral guide flange on the inside of the bend can easily be lost. An important reason for the loss of a track guidance contact on the side of the inside of the bend in the case of tight bends is that the lateral guide flange on the inside of the bend is often omitted on tight bends because the lateral offset of the trailing rear axle is greater on tight bends than the clear space between the vehicle wheels and the lateral guide flanges when travelling in a straight line.
The train formation of track-guidable dual-mode buses on different routes becomes expedient if there is a high volume of traffic and they share the same route some of the way, because buses coupled together are regarded as one vehicle unit and consequently more omnibuses per unit of time can be fed through a busy track guidance section. A disadvantage with the known coupling system for omnibuses is that the coupling device is very short and thus cannot be seen during the coupling operation by the driver of the omnibus coupled at the rear; it is therefore always necessary as a practical matter to have a second person during coupling. A further disadvantage of the known omnibus is that the front and rear couplings disfigure the end faces of the omnibuses in a very ugly or unattractive manner.
An object of the invention is to design the omnibus of the basic generic type in such a way that, despite the attachment of front and rear couplings, the omnibuses can retain their customary appearance, accepted by the public, and that it is possible to couple a bus to a bus in front of it without a second person and without the driver getting out.
This object is achieved according to preferred embodiments of the invention by providing a combination of the following features;
(a) at least the front coupling is designed in the form of a bar which can be extended from the outer contour of the omnibus in travelling direction or retracted into it under remote control, and, in the not yet completely extended state, guided such that it can only be moved longitudinally; PA1 (b) the horizontal swivel bearings of the front coupling and of the rear coupling are--in the extended state of the parts of the coupling device prepared for a coupling of omnibuses--in each case arranged in the area of the front or of the rear outer contour, respectively, of the omnibus; PA1 (c) in the at least partially extended state necessary for coupling, the bar is held by buffers, stops or the like with respect to the vertical direction and the horizontal direction in the coupling position necessary for the coupling of the omnibuses standing in line one behind the other in travelling direction; PA1 (d) at least the driving functions such as traction, gear changing and braking of the omnibuses suitable for train formation can be operated in a way known per se in each case from the driver's position under remote control; PA1 (e) as well as the coupling heads, multiple plug-in connectors for compressed air and electric and/or fluid control lines are also provided for the driving functions; and PA1 (f) means for switching the remote-controlled operation of the driving functions are provided, such that the driving functions of the coupled omnibus or omnibuses can be predetermined or controlled simultaneously and uniformly from the driver's position of the first omnibus of the train.
Thanks to the extendibility and retractability of the front and/or rear coupling, they retain their pleasant appearance when the omnibuses are used on their own, because the couplings can be retracted to behind the outer shell of the vehicles. On the other hand, the couplings, that is at least the front coupling, can be extended to such an extent that the coupling heads can be seen during the coupling operation by the driver of the rear omnibus and can be correspondingly directed.
In order to prevent buckling of the train during combined travel, simultaneous and uniform traction and brake control of all omnibuses joined in the train from the front driver's position is provided. The coupling device therefore does not serve for towing force or braking force transfer, but only for keeping the omnibuses apart. All they have to do is transfer differences in the towing or braking forces between the individual omnibuses, which experience shows are only so small however that there is no danger of buckling, even with the coupling bar in angled position, because the lateral guide forces of the vehicle axles and of the track guidance device are adequately large to be able to absorb reliably the lateral force components induced by an angled position of the coupling bar and differences in towing and braking forces.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.